require 'active_support/core_ext/module/delegation' module ActiveSupport # Notifications provides an instrumentation API for Ruby. To instrument an # action in Ruby you just need to do: # # ActiveSupport::Notifications.instrument(:render, :extra => :information) do # render :text => "Foo" # end # # You can consume those events and the information they provide by registering # a subscriber. For instance, let's store all instrumented events in an array: # # @events = [] # # ActiveSupport::Notifications.subscribe do |*args| # @events << ActiveSupport::Notifications::Event.new(*args) # end # # ActiveSupport::Notifications.instrument(:render, :extra => :information) do # render :text => "Foo" # end # # event = @events.first # event.name #=> :render # event.duration #=> 10 (in miliseconds) # event.result #=> "Foo" # event.payload #=> { :extra => :information } # # When subscribing to Notifications, you can pass a pattern, to only consume # events that match the pattern: # # ActiveSupport::Notifications.subscribe(/render/) do |event| # @render_events << event # end # # Notifications ships with a queue implementation that consumes and publish events # to subscribers in a thread. You can use any queue implementation you want. # module Notifications autoload :Instrumenter, 'active_support/notifications/instrumenter' autoload :Event, 'active_support/notifications/instrumenter' autoload :Fanout, 'active_support/notifications/fanout' class << self attr_writer :notifier delegate :publish, :subscribe, :to => :notifier delegate :instrument, :instrument!, :to => :instrumenter def notifier @notifier ||= Notifier.new end def instrumenter Thread.current[:"instrumentation_#{notifier.object_id}"] ||= Instrumenter.new(notifier) end end class Notifier def initialize(queue = Fanout.new) @queue = queue end def publish(*args) @queue.publish(*args) end def subscribe(pattern = nil, &block) @queue.bind(pattern).subscribe(&block) end def wait @queue.wait end end end end